All-Organic Battery Based on Deep Eutectic Solvent and Redox-Active Polymers

• Published in: ChemSusChem 2024-01, Vol.17 (1), p.e202301057-e202301057
• Main Authors: Uhl, Matthias, Sadeeda, Penert, Philipp, Schuster, Philipp A, Schick, Benjamin W, Muench, Simon, Farkas, Attila, Schubert, Ulrich S, Esser, Birgit, Kuehne, Alexander J C, Jacob, Timo
• Format: Article
• Language: English
• Subjects: Aqueous electrolytes; Electrolytes; Energy storage; Flammability; Polymers; Rechargeable batteries; Solvents; Storage systems
• ISSN: 1864-5631; 1864-564X
• DOI: 10.1002/cssc.202301057

Sustainable battery concepts are of great importance for the energy storage demands of the future. Organic batteries based on redox-active polymers are one class of promising storage systems to meet these demands, in particular when combined with environmentally friendly and safe electrolytes. Deep Eutectic Solvents (DESs) represent a class of electrolytes that can be produced from sustainable sources and exhibit in most cases no or only a small environmental impact. Because of their non-flammability, DESs are safe, while providing an electrochemical stability window almost comparable to established battery electrolytes and much broader than typical aqueous electrolytes. Here, we report the first all-organic battery cell based on a DES electrolyte, which in this case is composed of sodium bis(trifluoromethanesulfonyl)imide (NaTFSI) and N-methylacetamide (NMA) alongside the electrode active materials poly(2,2,6,6-tetramethylpiperidin-1-yl-oxyl methacrylate) (PTMA) and crosslinked poly(vinylbenzylviologen) (X-PVBV ). The resulting cell shows two voltage plateaus at 1.07 V and 1.58 V and achieves Coulombic efficiencies of 98 %. Surprisingly, the X-PVBV/X-PVBV redox couple turned out to be much more stable in NaTFSI : NMA 1 : 6 than the X-PVBV /X-PVBV couple, leading to asymmetric capacity fading during cycling tests.